15
The table below shows the maximum SLC wire lengths based on wire gauge and appliance
current load.
Table 5.
Maximum SLC Wire Length to Farthest Appliance Based on Appliance Current Load
Distance in Feet (Meters) to the Last Appliance
Alarm Current
18 AWG (0.82 mm
2
)
14 AWG (2.08 mm
2
)
12 AWG (3.31 mm
2
)
0.11 A
638 ft (194 m)
1,614 ft (492 m)
2,500 ft (762 m)
0.25 A
281 ft (86 m)
710 ft (216 m)
1,129 ft (344 m)
0.60 A
117 ft (36 m)
296 ft (90 m)
471 ft (144 m)
0.80 A
88 ft (27 m)
222 ft (68 m)
353 ft (108 m)
1.0 A
70 ft (21 m)
178 ft (54 m)
282 ft (86 m)
1.3 A
―
137 ft (42 m)
217 ft (66 m)
2.2 A
―
81 ft (25 m)
128 ft (39 m)
3.0 A
―
―
113 ft (34 m)
Distances based on 2.0 V line drop
If notification appliances on a given circuit are to be used for multiple notification zones for partial
evacuation (selective signaling), then either a Class A loop circuit configuration and isolators must be
used, with isolators bounding any wire segment that services a notification zone; or, the NAC riser
must be installed in accordance with Survivability From Attack by Fire Requirements in NFPA 2002
ED. Section 6.9.4, using one or more of the following:
2 hour rated cable assembly
a 2 hour rated shaft or enclosure
2 hour rated stairwell in building fully sprinklered in accordance with NFPA 13
The table below shows the maximum SLC wire length based on wire type and supervision
communications.
Table 6. Maximum SLC Wire Length to Farthest Appliance Based on Supervision Communications
Distance in Feet (Meters) to the Last Appliance
Unit Load Range
18 AWG (0.82 mm
2
)
14 AWG (2.08 mm
2
)
12 AWG (3.31 mm
2
)
1 to 3
305 ft (93 m)
772 ft (235 m)
1,228 ft (374 m)
4 to 7
260 ft (79 m)
657 ft (200 m)
1,046 ft (319 m)
8 to 13
213 ft (65 m)
538 ft (164 m)
856 ft (261 m)
14 to 20
175 ft (53 m)
444 ft (135 m)
706 ft (215 m)
21 to 30
140 ft (43 m)
355 ft (108 m)
565 ft (172 m)
31 to 40
117 ft (36 m)
296 ft (90 m)
471 ft (144 m)
41 to 50
100 ft (30 m)
254 ft (77 m)
403 ft (123 m)
51 to 60
―
222 ft (68 m)
353 ft (108 m)
61 to 75
―
187 ft (57 m)
297 ft (91 m)
Continued on next page
Wiring Class A Circuits,
Continued
Class A Guidelines
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